drm/exynos: gsc: fix wrong bitwise operation for swap detection

This change “drm/exynos: gsc: fix wrong bitwise operation for swap detection” in Linux kernel is authored by Hyungwon Hwang <human.hwang [at] samsung.com> on Wed Jul 1 19:09:24 2015 +0900.

drm/exynos: gsc: fix wrong bitwise operation for swap detection

The bits for rotation are not used as exclusively. So GSC_IN_ROT_270 can
not be used for swap detection. The definition of it is same with
GSC_IN_ROT_MASK. It is enough to check GSC_IN_ROT_90 bit is set or not to
check whether width / height size swapping is needed.

Signed-off-by: Hyungwon Hwang <human.hwang@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit f2d0160.

There are 6 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/gpu/drm/exynos/exynos_drm_gsc.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_gsc.c b/drivers/gpu/drm/exynos/exynos_drm_gsc.c
index 8040ed2..f1c6b76 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gsc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gsc.c
@@ -593,8 +593,7 @@ static int gsc_src_set_transf(struct device *dev,
 
 	gsc_write(cfg, GSC_IN_CON);
 
-	ctx->rotation = cfg &
-		(GSC_IN_ROT_90 | GSC_IN_ROT_270) ? 1 : 0;
+	ctx->rotation = (cfg & GSC_IN_ROT_90) ? 1 : 0;
 	*swap = ctx->rotation;
 
 	return 0;
@@ -857,8 +856,7 @@ static int gsc_dst_set_transf(struct device *dev,
 
 	gsc_write(cfg, GSC_IN_CON);
 
-	ctx->rotation = cfg &
-		(GSC_IN_ROT_90 | GSC_IN_ROT_270) ? 1 : 0;
+	ctx->rotation = (cfg & GSC_IN_ROT_90) ? 1 : 0;
 	*swap = ctx->rotation;
 
 	return 0;

The commit for this change in Linux stable tree is f2d0160 (patch).

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